Printing assembly controlled by electric pulses



Jan. 21, 1969 s. T. BAKARDJIEV ET AL 3,422,754

PRINTING ASSEMBLY CONTROLLED BY ELECTRIC PULSES Sheet Filed Feb. 8, 1967N VE N T O R S fifefqn Fdomv BAKAR DJ l E V U?" T J IN T%%6V o by (9-203131; Afforngy Jan. 21, 1969 s. T. BAKARDJIEV ET AL. 3,422,754

PRINTING ASSEMBLY CONTROLLED BY ELECTRIC PULSES Filed Feb. 8, 1967 Sheet2 Of 2 INVENTORSZ Sl'efom Todorov BAKARDJIEV lvom T'enev STANTCHEVLubomir Iordqnov ANTONW "weir ATTorney H United States Patent 3,422,754PRINTING ASSEMBLY CONTROLLED BY ELECTRIC PULSES Stefan T. Bakardjiev,Ivan Teuev Stantchev, and Dubomir Iordanov Antonov, Sofia, Bulgaria,assignors to Zentralen Institut Po Iztchislitelna Technika, Sofia,Bulgaria,

Filed Feb. 8, 1967, Ser. No. 615,016

Claims priority, application Bulgaria, Mar. 9, 1966, [-217 US. Cl.101-79 7 Claims Int. Cl. B413 45/00, 1/60 ABSTRACT OF THE DISCLOSURE Aprinting assembly wherein a rotary printing member and a rotary ratchetmember are connected to each other for rotation together about a givenaxis so as to locate a selected one of a series of printing types, whichare angularly distributed along a peripheral portion of the printingmember, at a printing position, upon turning of the members around thisaxis from a predetermined starting position. The ratchet member has aseries of ratchet teeth corresponding to the number of printing typeswhich are angularly distributed along the peripheral portion of theprinting member. An armature, which has the configuration of a pawl,coacts with the teeth of the ratchet member to control the stepping ofthe latter together with the printing member around the axis of rotationthereof. A spring urges the printing member to turn from the startingposition so as to locate a selected type at the printing location. Anelectromagnetic means coacts with the armature to oscillate the latterso as to control the stepping of the printing member by the number ofpulses transmitted to the electromagnetic means, this number of pulsescorresponding to the number of oscillations of the pawl so as to controlthe number of steps through which the printing member turns to locate aselected type at the printing position.

The present invention relates to printing assemblies. In particular, thepresent invention relates to that type of printing assembly where arotary printing member has a peripheral portion provided with a luralityof angularly distributed types, a selected one of which is to be locatedat a printing position.

Devices of the aforedescribed general type are known and are, forexample, described in US. Patents, Nos. 3,156,181 and 3,173,359.

While devices of the above general type are known for locating selectedtypes at a printing location, in one type of known construction electricpulses not only serve to control the movement of the printing member,but in addition the electrical energy is used for driving the printingmember, so that relatively strong electric pulses are required,resulting in complex and expensive pulse generators.

There are also known constructions where the electrical controls fordisplacing a selected type to the printing position are separate fromthe driving structure which drives the printing member, but with thistype of construction the selection is controlled by a light fixingelement which coacts with the electric pulses, resulting also in acomplex arrangement. This latter type of construction requires a systemfor synchronizing themovement of the printing member with the operationof the electric pulse generator, so that a complex pulse generator isrequired, and this latter type of structure has frequent serviceproblems.

It is accordingly a primary object of the present invention to provide aprinting assembly of the above general type which will avoid the abovedrawbacks.

In particular, it is an object of the present invention to provide aprinting assembly in which the selection of a given printing type iscontrolled by electric pulses while the printing member itself is drivenfrom a separate source.

It is also an object of the invention to provide an exceedingly simple,compact structure which will operate very reliably to produce thedesired results.

With the structure of the invention a rotary printing member has aperipheral portion rovided with a series of printing types which areangularly distributed at the peripheral portion of the printing memberaround the turning axis thereof, a suitable support means being providedto support the printing member for rotary movement about this axis. Aratchet member is fixed to the printing member for rotation therewith,and the ratchet member has a series of ratchet teeth also angularlydistributed about the latter axis and corresponding to the series ofprinting types. A spring means coacts with one of these members forturning both of them about the latter axis so as to locate a selectedprinting type at the printing position. An armature is provided, thisarmature having the construction of a pawl which coacts with the ratchetteeth to control the stepping of the printing member by the force of thespring means, and an electromagnetic means cooperates with the armaturefor oscillating the latter so as to control the stepping of the printingmember in accordance with the pulses received by the electromagneticmeans. In this way a selected type will be located at a printingposition.

The invention is illustrated by way of example in the accompanyingdrawing which forms part of this application and in which:

FIG. 1 is an exploded perspective illustration of one of a series ofassemblies according to the invention; and

FIG. 1A shows part of the structure of FIG. 1 in a different position.

FIG. 2 illustrates diagrammatically in plan view the device illustratedin FIGS. 1 and 1A.

Referring now to the drawing, there is shown in FIG. 1 a rotary printingmember 2 and a rotary ratchet member 3 fixed to the member 2 forrotation therewith. The members 2 and 3 are integrally connected witheach other, are located in a common plane, and form a single plate 1.This plate is formed with an opening through which the common turningaxis of the members 2 and 3 extends, and a stationary shaft 4 extendsthrough this opening and forms a support means for the plate 1, thelatter being freely turnable on the shaft 4, so that in this way theintegrally connected printing member 2 and ratchet member 3 are capableof turning as a unit about the axis of the shaft 4. The printing member2 has at its outer periphery a series of angularly displaced types whichare angularly distributed about the axis of the shaft 4, while theratchet member 3 is angularly displaced with respect to the entireprinting member 2 and has its ratchet teeth also angularly distributedabout the axis of the shaft 4. The number of ratchet teeth of coursecorrespond to the number of printing types, and the angular positions ofthe ratchet teeth correspond to the angular positions of the printingtypes, so that in this way it will become possible, in a mannerdescribed in greater detail below, to locate a selected printing type ata printing position which is shown in phantom lines in the drawing.

A spring means 5 is operatively connected with the plate 1, so that inthis way it is connected to one of the members 2 or 3, and this springmeans 5 acts to turn the members 2 and 3 from a predetermined startingposition to a position where a selected one of the types of the printingmember 2 will be located in a printing position. In the illustratedexample the plate 1 is formed in a side surface thereof with an annularrecess 20 surrounding the shaft 4, and the spring is in the form of aspiral spring situated within this recess and having its inner end fixedto the stationary shaft 4. The outer end of the spiral spring 5 is fixedto the plate 1 in a notch 21 thereof which communicates with the outerperiphery of the annular recess in which the spring 5 is situated, asindicated diagrammatically in FIGS. 1 and 1A, so that with thisconstruction the spring 5 seeks to turn the plate 1 in a clockwisedirection, as indicated by the arrow in the drawing. The inner end ofspring 5 is fixed to shaft 4 by a pin 19.

The structure of the invention includes an armature 7 in the form of apawl supported for swinging movement about an axis parallel to the shaft4 and having an upper tooth 6 which coacts with the ratchet teeth of theratchet member 3 in the manner shown in the drawing. A second springmeans 8 coacts with the pawl 7 to turn the latter to a position whichwill locate the pawl tooth 6 in engagement with one of the ratchet teethso as to prevent turning of the plate 1 by the spring 5. Anelectromagnetic means 9 coacts with the pawl 7 for oscillating thelatter, and in the position of the parts shown in FIG. 1 theelectromagnetic means is unenergized so that the spring 8 locates thetooth 6 in engagement with one of the ratchet teeth. When theelectromagnetic means 9 is energized it will swing the armature 7 in aclockwise direction, in opposition to the spring 8, to the dotted lineposition shown in FIG. 2 and the position shown in solid lines in FIG.1A, with the result that the pawl tooth 6 will be displaced away fromthe ratchet so that the spring 5 can turn the plate 1. Theelectromagnetic means 9 is controlled with low power pulses receivedfrom a generator 10, and in the short time intervals betweenthe pulsesthe spring 8 returns the pawl 7 to the position thereof shown in FIG. 1,so that in response to a given number of pulses delivered to theelectromagnetic means 9 by the generator 10 the pawl 7 will beoscillated a given number of times, thus causing the plate 1 to bestepped around the shaft 4 a number of times which will locate aselected one of the types of the printing member 2 at the printingposition shown in phantom lines in the drawing. Thus, the spring 5 willturn the plate 1 through an angle corresponding to the number of pulsesreceived by the electromagnetic means 9, and in this way a selected typewill be located at the printing location.

Thus, the movement of plate 1 is controlled by the flat, U-shapedelectromagnet 9 which swings the armature 7 which acts as a pawl andwhich is in the form of an escapement anchor. This armature 7 rocksabout a stationary pin 14 which is received in an opening 16 of pawl 7and which has its axis parallel to the axis of the shaft 4.

In order to keep losses at a minimum in the electromagnetic field at theclearance between the armature 7 and the pole 22 of magnet 9, the pawl 7has a portion 18 in the configuration of an arc of a circle whose centeris in the axis of the pin 14. In order to achieve a maximum turningmoment about the pin 14, the upper end of the pawl 7 is inclined at anappropriate angle so that the pawl 7 has at this region an inclinedsurface 17 which lies fiush against the end of the pole 23 when themagnet 9 is energized.

The escapement type of pawl 7 has a pair of teeth 6 and whichalternately coact with the teeth of the ratchet 3. The spring 8 acts tomaintain the tooth 6 of the pawl 7 in engagement with a ratchet toothwhen the electromagnet 9 is unenergized, so as to prevent furtherturning of the plate 1 by the spring 5. When the electromagnet 9 isenergized, however, the pawl 7 is swung in a clockwise direction inopposition to the spring 8 to the position shown in FIG. 1A, so that thetooth 6 moves away from the ratchet teeth and the spring 5 turns theplate through half the distance between a pair of adjacent ratchet teethbecause the tooth 15 of the pawl 7 engages a ratchet tooth. In the shortinterval prior to the next impulse the spring 8 disengages the tooth 15from the ratchet and swings the pawl 7 back to its initial position sothat the tooth 6 will engage the next ratchet tooth, and in this wayeach impulse sequence of two successive pulses provides a movement ofthe plate 1 through a distance from one ratchet tooth to the nextratchet tooth so that the rotary printing member is stepped through adistance equal to one printing type.

It will be noted that with this construction the plate 1 need not bevery thick so that an exceedingly compact arrangement is provided with aseries of structures as described above situated one next to the other,on the common shaft 4, and thus a series of printing members 2 arelocated beside each other and can all be turned through selected anglesrespectively so as to locate a series of printing types in ahorizontally aligned condition at the printing osition. Because of thecompact structure of the invention all of the printing assemblies can belocated one directly next to each other, occupying a relatively smallamount of space with the horizontally arranged printing types located ata convenient distance from each other.

After all of the plates 1 have been turned to the selected angularpositions respectively so that a horizontal series of printing typescarried by the horizontally arranged printing members 2 are all locatedat the printing position, the platen or roller 11 will displace thepaper to gether with a tape of a suitable color against the printingelements which are in the printing positions, so that the impressionsthereof will be transferred to the paper.

The above operations are repeated to carry out a series of printingoperations. A return means is provided for returning all of the plates 1to predetermined starting positions where they are all angularlyaligned, and this return means takes the form of bail 12 having a pairof arms turnable on a shaft 4 and extending radially therefrom andinterconnected by a rod 13 which extends parallel to the shaft 4 andwhich is shown fragmentarily in FIG. 1. Thus, the rod of the bail 12will, upon turning of the ball 12 in a counter-clockwise direction in aknown way, as indicated in the drawing, engage the shoulder formed by asubstantially radial edge at one end of the printing member 2, wherethis latter end joins the adjacent end of the ratchet member 3, so thatin this way the return means formed by the bail 12 will act on the plate1 to return the printing and ratchet members to their predeterminedstarting position. It will be noted that during this return movement ofthe assembly to its starting position the spiral spring means 5 is woundup in preparation for the next operation. The return means 12 isactuated by an electromechanical drive which acts on the return means 12to provide for the latter a single swinging movement around the shaft 4in order to return the entire series of printing assemblies which arecarried by the shaft 4 simultaneously to their starting positions.

What is claimed is:

1. In a printing assembly, a rotary printing member having apredetermined axis of rotation and having an outer peripheral portioncarrying a series of types which are angularly distributed about saidaxis, support means supporting said printing member for rotary movementabout said axis, a toothed ratchet member fixed to said rotary printingmember for rotary movement therewith and having a plurality of ratchetteeth respectively corresponding to said types and also angularlydistributed about said axis, spring means operatively connected to oneof said members for urging them from a predetermined starting positionabout said axis to a position which will locate a selected type at aprinting position, an armature having the construction of a pawl memberand coacting with said teeth of said ratchet member for stepping saidprinting member around said axis in response to the force exerted onsaid printing member by said spring means until said selected type islocated at said printing position and electromagnetic means forreceiving a selected number of pulses and coacting with said pawl memberfor oscillating the latter with respect to said ratchet member until theselected type is located at said printing position, a second springmeans coacting with said pawl member for urging the latter intoengagement with said ratchet member to prevent turning of the latter andsaid printing member by said first-mentioned spring means, said secondspring means turning said pawl member in one direction and saidelectromagnetic means turning said pawl member in opposition to saidsecond spring means in an opposite direction to provide the oscillationsof said pawl member in accordance with the number of pulses delivered tosaid electromagnetic means so as to displace a selected type to theprinting position.

2. The combination of claim 1 and wherein a return means coacts with theinterconnected printing and ratchet members for returning them to saidstarting position after a selected type has been located at saidprinting position.

3. The combination of claim 1 and wherein said printing and ratchetmembers are integrally connected to each other.

4. The combination of claim 3 and wherein said printing member andratchet member are located in a common plane with said ratchet memberangularly displaced with respect to said printing member.

5. The combination of claim 4 and wherein said printing member andratchet member together form a single plate, said plate being formedwith an opening through which said axis extends, and said support meansincluding a shaft around which said printing and ratchet members areturnable, said plate being formed in one side surface with a recesssurrounding said shaft, and said firstmentioned spring means beingsituated in said recess and connected to said shaft and plate for urgingthe latter to turn in a direction which will displace a selected type tosaid printing position.

6. The combination of claim 5 and wherein said printing member has alarger radius than said ratchet memher and projects radially beyond thelatter defining with said ratchet member, at one end of the latter andat one end of said printing member, a substantially radial shoulder, andreturn means coacting with said shoulder for turning said plate inopposition to said first-mentioned spring means to said startingposition after a selected printing member has been located at saidprinting position.

7. The combination of claim 1 and wherein said pawl member is in theform of an escapement anchor turnable about an axis parallel to the axisof rotation of said printing member and having a pair of teethalternately coacting with the teeth of said ratchet member for indexingthe latter, said pawl member having an arcuate surface portion extendingalong a circle whose center is in the turning axis of said pawl memberand said electromagnetic means having one pole terminating in a concavearcuate end face located closely adjacent to said arcuate surfaceportion of said pawl member, said pawl member having spaced from saidarcuate surface portion thereof an inclined straight surface portion andsaid electromagnetic means having a second pole terminating in astraight end face which has a flush engagement with said inclinedstraight surface portion of said pawl member when said electromagneticmeans is energized.

References Cited UNITED STATES PATENTS 1,195,992 8/1916 Joline 101--191,978,330 10/1934 Schultes 101-28 2,417,865 3/1947 Douglass 101-72,576,041 11/1951 Pitts 101-99 3,019,724 2/1962 Hoflmann 1017 3,156,18111/1964 Dubin 101-110 3,173,359 3/1965 Turner 101100 3,269,510 8/1966Peters 101l8 X WILLIAM B. PENN, Primary Examiner.

U.S. Cl. X.R. 10199,

